larry@uunet.uu.net (Larry Lippman) (04/01/91)
In article <telecom11.251.4@eecs.nwu.edu> kent@sunfs3.bos.camex.com (Kent Borg) writes: >> ANI was added around 1973, before that you >> dialed a toll call as 1+ ..., but the operator had to ask "Number, >> please?"; you KNEW she meant the number you were calling from! ANI from WECo was in service as of 1960 for SxS CO's. This was ANI-B, which used a 5 KHz or so identification tone. ANI-B was quickly replaced with ANI-C by 1963 or so. ANI-C and the later ANI-D became the standard methods of providing ANI in SxS CO's, and I would not be surprised if some is still in service in rural areas. ANI-C and ANI-D used short 340 volt DC pulses on the sleeve lead that were decoded using a neon lamp matrix. > I never knew. I always had to ask what she meant. I had assumed that > they knew where I was calling from (you mean I could have lied and > gotten away with it? -- never occured to me), yet I had just dialed > the number I wanted, so why would she ask that? Fraud by giving an incorrect number to the ONI operator was a problem, but not that serious. The first line of defense was that the called party (we know *that* number for certain!) would be contacted should the billing number not be in service, or should the call charges be contested by the party upon whose bill they appeared. Some ONI fraud was easy to spot - like giving a telephone number from a CO other than the one calling from! The ONI operator certainly knew what CO belonged to the trunk being answered. In some areas the ONI operator had a chart of valid thousands and hundreds groups for each CO served by the ONI position; this somewhat reduced the problem of being given non-existent numbers. There was a more sophisticated approach tried in some areas. The ONI position automatically used the keyed numbers to access a special test trunk back to the originating SxS CO, which used a special test distributor and connector to ascertain if the calling number that was furnished to the ONI operator was busy. If it did test busy, it was presumed that the number furnished to the ONI operator *could* be valid. It it did not test busy, then it was presumed that the number furnished to the ONI operator was phony. I never personally saw one of the above verification systems since comparatively few were installed due to their marginal value at reducing fraud. Larry Lippman @ Recognition Research Corp. "Have you hugged your cat today?" VOICE: 716/688-1231 {boulder, rutgers, watmath}!ub!kitty!larry FAX: 716/741-9635 [note: ub=acsu.buffalo.edu] uunet!/ \aerion!larry